Testing system



Aug. 25, 1931. R w, BURNS 1,820,116

TESTING SYSTEM Filed Oct. 8, 1930 INVENTOR Z2 iWbzu ms 1 BY i373 WATTORNEY Patented Aug. 25, 1931 UNITED STATES @FFKCE ROY W. BURNS, OFBROOKLYN, NEW YORK, ASSIGNQR TO AMERICAN TELEPHONE AND TELEGRAPHCOMPANY, A CORTORATION OF NEW YORK TESTING SYSTEM This invention relatesto testing systems. More particularly, this invention relates toarrangements for testing switchboard jacks.

This invention provides arr; igements for 5 testing switchboard jacks.The testing arrangements contemplate the use of a number of gauges inthe form of plugs, specially designed and specially built, the elementsof which are arranged to make electrical con tact with the various jackelements in the same manner as the ordinary switchboard plugs. The plugsused for testing purposes are so designed that if the various jacks makesatisfactory contact with them, the jacks will function satisfactorilywhen engaged with the ordinary switchboard plugs used in the telephoneservice. The arrangements hereinafter described provide means forproducing and transmitting a distinctive 20 signal to one or moremaintenance men when any one of the various jacks fail to makesatisfactory electrical contact with any one of the testing plugs.

The features of this invention represent great improvements over thejack testing arrangements of the prior art. The means heretoforeemployed for giving the maintenance man or men an indication of thefailure of any one of a plurality of jacks to make corresponding testingplug, involved the application of tone, i. e. alternating current or itsequivalent, to the associated line or trunk circuit or the employment ofan electrical condition simulating that of the circuit. Before testingany jack, it was necessary for the maintenance man to determine whetherthe associated circuit was in use and it was further necessary to removethe circuit from service when the test was being made. Thesedifliculties are obviated in the practice of this invention.

lVhile this invention will be pointed out with particularity in theappended claims, the invention itself, both as to its objects andfeatures, will be better understood from the detailed descriptionhereinafter following when read in connection with the accompanyingdrawings in which Figure l represents an arrangement for determiningsatisfactory contact with the elements of a whether the contacts of aplurality of jacks properly engage the contacts of the plurality of testplugs; Fig. 2 schematically represents the fundamental elements of theinvention; and Fig. 3 discloses an arrangement for determining whetheror not the tip and ring contacts of any one of the plurality of jacksare short-circuited.

The arrangement shown in Fig. 1 is one in which busy circuits as well ascircuits not in use may be tested without takingany circuit out ofservice if it is idle or without interfering with service if the circuitis busy. This arrangement obviously has distinct advantages over thoseknown in the art especially because the jacks may be tested at any timeregardless of'whetner or not the associated circuits are in use and itis unnecessary for the maintenance man or men .toperform tests todetermine whether any circuit is busy.

-Referring to Fig. 1 of the drawings, the reference characters L L and Lrepresent three conductors forming one of a plurality of groups ofconductors wired across a telephone switchboard. Conductors L and Lextend well beyond the local exexchange and may, for instance, terminatein a subscribers line. Conductor L is mere.- ly considered a sleeveconductor and may be used only for signaling between various parts ofthe local ofiice. Conductors L L and L conductors L L and L andconductors L L and L form three other groups which are similarly wiredabout the telephone switchboard, all of which, however, are local to theexchange and are used merely for testing purposes.

Two jacks designated J and J as well as numerous others, are connectedto the con ductors L L and L These jacks are thus ordinarily plugged bythe telephone operator in connecting a partys circuit terminatingconductors L and L with some other circuit. These jacks may be locatedat adjoining sections of the switchboard, one or more of which may beplaced at each section of the board, all being wired, however, inparallel relationship, as shown.

Jack J as well as a number of other jacks of similar construction, maybe connected to the testing conductors L L and L Jack J represents oneof a number of jacks similarly connected to testing conductors L L and LJacks J and J among others, are connected in parallel relationship tothe test ing conductors L L and L Plugs P and P which are speciallydesigned for testing purposes may be caused to engage the jacks J and Jrespectively, and plug P which may be of ordinary design may be causedto engage jack J The tip, ring and sleeve sides of plugs P and P areconnected in parallel relationship. The plugs P P and P may be caused toengage jacks J J and J respectively. Plugs P and P may be connectedtotelephone head sets or receivers R and R respectively.

A key is designated K and this key includes two independently operableswitches S, and S The tip side of plug P is connected to the movableside of switch S The tip side of plug P is connected to the fixedcontact of switch S The ring side of plug P. is connected to the movableside of switch S The ring side of plug P is connected to the fixed:contact of switch S The sleeve sides of plugs P and P are connected toeach other.

The winding of a relay WV, is connected in series with a resistance Zand a battery B which may be composed of a plurality of dry cells, theseries circuit extending between conductors-L v and'L The armature ofrela W is "rounded and its contact is connected in series with thewinding of a relay and a battery B and ground. The armature of the relay7 is also grounded and its contact is connected toone of the terminalsof the primary winding of a transformer T The other terminal of thisprimary winding is connected to the ground through av circuit whichincludes the winding of a relay V and a battery B The armature of therelay and its contact shunt the winding of this relay. The secondarywinding of the transformer T is connected to the primary winding of atransformer T The latter transformer includes two secondary windingsdesignated Y and Y Y is connected in series with one of the primarywindings Y ofa transformer T these series windings, however, extendingto conductorsL and L Winding Y is connected in series with the otherprimary winding Y of transformer T and these series windings areconnected to the conductorsL and L The secondary winding of transformerT is connectedto the conduc torsL and L In operating this arrangement, PP P P P and P are caused to engage the jacksJ' J J J J and Jrespectively. Relay V will operate and it will remain operated whilethese plugs an v jacks areso the plugs engaged, current flowing frombattery B through resistance Z, the winding of relay WV conductor L thesleeve contacts of jack J and the plug P the sleeve contacts of plug Pand jack J conductor L the sleeve contacts of jack J 1 and plug P thesleeve contacts of plug P and jack J and conductor L Thereafter relaywill operate and remain operated as long as relay W is operated, currentflowing from battery B through the winding of relay W the armature andcontact of relay W and ground. Upon the closure of the contact of relayW by its armature, relay W will operate, current flowing from battery Bthrough the winding of relay the primary winding of the transformer Tthe armature and contact of relay W and ground. Upon the closure of thecontact of relay W by its armature, the winding of relay WV will becomeshort-circuited and, therefore, relay will release. Thereafter, currentwill flow through the winding of relay V over the circuit just traced,causing this relay to operate, and shortly thereafter this relay againwill be released. Thus, it will be apparent that current flowing throughthe winding of relay W will be regularly interrupted, thereby causing apulsating direct current to flow through the primary winding oftransformer T The presence of a pulsating current in the primary windingof transformer T will induce alternating voltages in the secondarywinding of this transformer and hence an alternating current of definitefrequency will flow through the circuit including the secondary windingof trans-former T and the primary winding of transformer T If the tipcontacts of plugs P P P and P properly engage the tip contacts of thejacks J J J and J alternating current will flow through the windings Yand Y this circuit including, in addition to these windings, conductorL,, the tip contacts of jack J and plug 1 the contact ofswitch. S thetip contacts of plug P and jack J con.- ductor L, the tip contactsof'jack J and plug P the tip contacts of plug-P and jack J 3 andconductor L Moreover, if the ring contacts of plugs P P P and P properlyengage the ring contacts of jacks J J J 3 and'tL, respectively,alternating current will flow through the windings Y and Y the completedcircuit including, in addition to these windings, conductor L the ringcontacts of jack J. and plug P the contacts of switch S the ringcontacts of. plug P and jack J conductor L ,.the ring contacts of jack Jand plug P the ring contacts of plugs P and jack J 3 and'conductor LWindings Y and Y will be so poled that their effects upon the secondarywinding of transformer T will be mutually opposite I and, since theamplitudes of ,the voltages imings pressed by these windings on thesecondary winding of transformer T are equal, sub stantially no currentwill flow over the circuit extending from the latter winding and JHence, the receivers R and R which are connected in parallelrelationship withthe tip and ring contacts of jacks J and Jrespectively, will not be energized. However, if either of the tipcontacts of jacks J or J do not make suitable connection with the tipcontacts of the plugs P or P current will flow through both of thereceivers R and R creating audible signals which notify the maintenancemen that there is trouble. Similarly, if either of the ring contacts ofthe jacks J or J 2 do not make suitable connection with the ringcontacts of plugs P or P current will also flow through both of thereceivers R and RI; and similarly attract the attention of themaintenance men.

\Vhenever a signal is heard at the receivers R and R it will benecessary to determine whether the tip orring sides of jacks J or J arefaulty. Switch S1 may be opened and if the signal at the receivers R andR persists, there will be positive indication that either of the tipcontacts of acks J or J 2 require adjustment or repair.

If, however, the audible signal is removed upon the opening of switch Sthen switch S will have to be opened and switch S closed. If the audiblesignal then persists,

there will be further indication that the ring sides of either jacks Jor J 2 are defective and require adjustment or repair.

Fig. 2 represents a schematic drawing of the circuit arrangement of theinvention. Three circuits are here designated Tip circuit, Ring circuitand Sleeve circuit. These three circuits include, among other things,the tip, ring and sleeve contacts, respectively, of the contacts J J J 3and J which will be connected to these circuits in the manner shown inFig. 1.

- The completion of the sleeve circuit through battery B and relay WVcauses an alternating voltage to be applied to the circuit E. Thiscauses alternating current to flow over both tip and ring circuits, thetip circuit including windings Y and Y which form parts of transformersT and T respectively, the ring circuit including wind- Y and Y, of theserespective transformers. Inasmuch as windings Y and Y are oppositelypoled, the currents impressed by these windings upon the secondarywinding of transformer T will have opposite phases and their effectswill neutralize each other. Consequently, the receivers R and R will notbe energized by alternating current. If, however, either the tip curcuitor the ring circuit is opened by virtue of a poor contact in one of theassociated jacks, ourto the tip and ring contacts of the jacks J rentwill fiowthrough both of these receivers R and R and thereby createaudible signals.

The arrangement shown in Fig. 3 of the drawings may be employed todetermine whether or not the tip and ring sides of any one of thevarious jacks which may be arranged in positions parallel to the jacks Jand J of Fig. 1 are short-circuited. This requires a preliminaryexamination to determine whether or not the line connected to the tipand ring sides of the jacks under test is busy.

Transformers T T and T are connected to each other in the manner shownin Fig. 1. The secondary winding of transformer T, is connected to atelephone receiver R. However, the secondary winding Y of transformer Tand the primary winding Y of the transformer T are in series with eachother in a circuit which includes the armature A of the relay W and itscontact and the armature of the relay W and its contact. The secondarywinding Y of transformer T and the primary winding Y of the transformerT are in series with each other in a circuit which includes the armatureA of relay T11 and its contact. The points designated M M and M may beconsidered the tip, ring and sleeve contacts of, for example, the jack J8 of Fig. 1. Similarly, the points designated M M and M may beconsidered the tip, ring and sleeve contacts of another jack such, forexample, as J; of Fig. 1. It is to be noted also that relays W W and Ware interconnected in the manner shown in Fig. 1, the winding of relay Whowever being connected to the contacts M and M.. through a resistance Zand a battery B The jack J10 may be considered the jack under test. Thesleeve of this jack is connected to ground through the winding of relayor a resistance Z as shown. The tip, ring and sleeve sides of a plug Pwhich is specially designed for short-circuiting tests may engage thejack J and, moreover, another plug P of ordinary construction may engagea testing jack J To determine whether the line connected to the tip andring sides of the jack J is busy, the plug P will be caused to engagethe jack J and the tip contact of plug P 5 will be moved to maketemporary contact with the sleeve side of jack J If the line is busy,current will flow over the circuit which includes the resistance Z thesleeve contact of jack J the tip contact of plug P the tip contacts ofplug P and jack J the armature A of relay W and its back contact, thewinding of a low voltage relay W and ground. The relay W will operateunder these con ditions only if the line is busy and the battery B andresistances Z and Z will be connected in series with each other, and,moreover, resistance Z will shunt the receiver R. A click will be heardin the receiver. If the line is not busy, however, no such click will beheard.

After it has been definitely determined that the line is not busy, jackJ may be tested to determine whether or not its tip and ring contactsare short-circuited. .The plug P will then be caused to engage jack JRelay 7 will operate by virtue of the flow of current from battery Bthrough a circuit which includes the winding of this relay, the sleevecontacts of jack J and plug P the sleeve contacts of plug 1? and jack Jresistance Z and ground. Thus, the windings Y and Y will be connected ina complete circuit through the armature A of relay and its contact.Moreover, the windings Y and Y will be connected in a complete circuitthrough the armature A of relay and its contact and armature of relay Wand its contact.

Inasmuch as the armature A of relay grounds one side of the primarywinding of transformer T and inasmuch as the other side of this windingis grounded through the winding of relay and battery 13,, an alternatingcurrent will be transmitted through the windings Y and Y to the windingsY and Y If the tip and ring contacts of jack J are short-circuited,however, a similar current of opposite phase will flow through thewindings Y and Y to the receiver R. These currents will neutralize eachother and no current will flow through the receiver R. If, however, thetip and ring contacts of jack J become short-circuited when the plug Pis caused to engage the jack J the relay W will then operate, currentflowing from battery B through the left-hand winding of relay W thecontact of jack J and plug P the ring contacts of plug P and jack J thetip contacts of jack J and plug P the tip contacts of plug P and jackJ11, the armature A of relay W and its front contact, the right-handwinding of relay WV and ground. The opening of the circuit to thewinding Y at the contact associated with the armature of the relay Wcauses current to flow through the secondary winding of-transformer T toenergize the receiver R.

lVhile this invention has been disclosed in certain particulararrangements merely for the purpose of illustration, it will beunderstood that the general principles of this invention may be appliedto other and widely varied organizations without departing from thespirit of the invention and the scope of the appended claims.

What is claimed is: p

1. A testing system including a plurality of jacks to be tested, aplurality of plugs each of which engages one of said jacks,

circuits, and receiving means coupled to said pair of circuits, saidpair of circuits being poled so that their effects on said recelvingmeans will be mutually opposite.

2. A'testing system including a plurality of jacks to be tested, aplurality of plugs each of which engages one of said jacks, a source ofalternating current, receiving means, a circuit coupling said source ofalternating current with said receiving means and including the tipsides of said jacks and plugs in series relationship, another circuitcoupling said source of alternating current with said receiving meansand including ring sides of said jacks and plugs in series relationship,and means connected to both of said circuits to open either of them.

3. The combination of a plurality of jacks, a plurality of plugs, eachjack and each plug having tip, ring and sleeve contacts, apparatusincluding the sleeve contacts of: all of said plugs and jacks forproducing pulsating currents, a first circuit coupled to said apparatusand including the tip contacts I of all of said plugs and jacks forderiving alternating current of one phase, a second circuit coupled tosaid apparatus and including the ring contacts of all of said plugs andjacks for deriving alternating current of opposite phase, and receivingmeans coupled to said first and second circuits.

4. The combination of a receiver, a plurality of jacks to be tested, aplurality of test plugs, a source of alternating potential, a firstcircuit including one of the contacts of each of'said plugs and thecorresponding contact of each of said jacks and coupling said receiverwith said source, and a second circuit including another of the contactsof each of said plugs and corresponding contact of each of said jacksalso coupling said receiver with said source.

In testimony whereof, I have signed my name to this specification this7th day of ROY W. BURNS.

' October 1930.

